Abstract: A contrast detection analyzer for detecting all edges sensed during a cirar scan and their angles with respect to vertical, wherein an edge near the center of the scan is detected, the angle is measured regardless of the light or dark orientation, and the exclusivity of the edge is determined. The analyzer output is in a digitized format suitable for computer calculations.

Abstract: 1. In a pulse-repetition frequency discriminator, the combination compris: gA. a pulse generator for generating pulses at a predetermined reference frequency,B. a gate generator coupled to said pulse generator and being responsive to the generated pulses to generate a gate signal having a width of a predetermined percentage of the repetition period of the predetermined reference frequency,C. ramp generator means coupled to said gate generator for converting said gate signal into a triangular shaped signal,D. a normally closed gate circuit coupled to said ramp generator means and to an input terminal adapted to receive radar pulses of interest and being responsive to received radar pulses having a frequency within said gate signal to pass a portion of said triangular shaped signal,E.